Extracting area of DEM above where 60% of region lies using ArcGIS Desktop?
I believe you are just looking for the 60th percentile value for your raster. The easiest way to do this probably is through the histogram functionality. Right click on the layer in the Table of Contents, then go Layer Properties > Symbology > Classified > Classify. Choose Quantile as the Method, and use 10 classes. The 6th class will then begin at the 60% percentile value. See the below image for an example.
If you want to specify other percentage values, you can press the "%" symbol on the right side of the Classification window, next to where it says "Break Values."
An alternate approach to the proposed DEM extraction, assuming you have Spatial Analyst, would be to:
- Use the 'Slice' tool with the "EQUAL AREA" method and 5 or 10 zones.
Then you could either:
a) Re-classify the Slice output to create a mask to extract your DEM
-- or --
b) Use it with the 'CON' tool or Raster Calculator to mask out your DEM on the top 3 or 6 zones (respectively to the number of Slice zones defined)
Also, Slice seems to get somewhat more accurate quantiles than the Quantile classification method (as indicated by @whuber on 2011-11-28 20:29)